Of course, it seems wasteful to need insanely fast access to things like movies or media/archival data in your home library.
http://www.wdc.com/en/products/Products.asp?DriveID=821 http://www.ocztechnology.com/products/solid-state-drives/hsd...
OCD IBIS Power: 6.6 Watts Idle 9.5 Watts Active
WD VelociRaptor Power: 4.30 Watts Idle 6.20 Watts Active
Now we do the math. A total of 9600 GB would be 10 OCD disk or 16 VelociRaptor disk.
16 x 6.20 = 99.2 --WD VelociRaptor
10 x 9.5 = 95 --OCD IBIS
Similar is true for idle.
If we were not limited to VelociRaptor, when you get into some of the very slow but very huge disks (1-2 TB), sure, you could beat the rather specific OCD IBIS models on Capacity-Per-Watt. But it is very unfair to open only one side of the rotating vs. ssd comparison to every disk made, and there are higher capacity SSD's with even better power consumption numbers than the OCD IBIS.
As you noted, the metric of Cost-Per-Capacity is often 10 or more times more favorable for rotating disks. If you don't have a valid _need_ for the speed offered by SSDs, they are certainly not worth the added costs.
It was not my intent to be argumentative - I just read your post and thought, power consumption as a benefit, are you sure you've done the math on this?
By the way, I couldn't find any 2 TB drives that were not PCI-X, so I do stand by my original analysis. With 1 TB SSDs, you'll still need 2x the servers. If you can piece together an SSD solution, ignoring cost, and including server wattage that can beat out an array of 2 TB drives on wattage, I will retract my original statement. You can use the idle power as the active power for the drives.